Trans-1, 2-bis(amino-methyl)cyclobutane and its preparation by hydrogenation of 1, 2-dicyanocyclobutane



United States Patent TRANS 1,2 BIS(AM1N0-METHYL)CYCLOBUTANE AND ITS PREPARATION BY HYDROGENATION OF 1,2-DICYANOCYCLOBUTANE Ralph Courtenay Schreyer, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del, a corporation of Delaware No Drawing. Filed Mar. 22, 1961, Ser. No. 97,454

2 Claims. (Cl. 260-563) I This invention relates to 1,2-bis(aminomethy1)cyclobutane, 3-aza(3.2.0)bicycloheptane, and to a process for their production. More particularly, this invention relates to trans-1,2-bis(aminomethyl)cyclobutane and to a process for the production of this compound together With 3-aza(3.2.0)bicycloheptane by the hydrogenation of 1,2- dicyanocyclobutane. This invention also relates to a novel class of polycarboxylamides made by the polymer ization of trans-1,2-bis(aminomethyl) cyclobutane with dicarboxylic acids.

One object of this invention is to provide the novel diamine, trans 1,2-bis(arninomethyl)cyclobutane. Another object of this invention is to provide the novel secondary amine, 3-aza(3.2.0)bicycloheptane and a process for its preparation. Another object of this invention is to provide a process for the, production of trans-1,2-bisaminomethyl cyclobutane and 3-a2a 3 .20) bicycloheptane, by hydrogenation of 1,2-dicyanocyclobutane. Still another object of this invention is to provide a process for the production of trans-1,2-bis(aminomethyl)cyclobutane in high yield with a minimum production of byproducts. Still another object of this invention is to provide a process for the isomerization of cis-LZ-dicyanocyclobutane to trans-1,2-dicyanocyclobutane. It is also an object f this invention to'provide a novel class of nylon resins made by the condensation polymerization of trans-1,2-bis- (aminomethyl) cyclobutane with dicarboxylic acids. Other objects and advantages of this invention will appear hereinafter.

It has been discovered, in accordance with the objects of this invention, that 1,2-dicyanocyclobut-ane can be hydrogenated in the presence of ammonia and in the liquid phase, under at least about 100 atmospheres of hydrogen, and preferably under from about 400 to about 1000 atmospheres of hydrogen, over a hydrogenation catalyst, comprising a transition metal of Group'VIlI of the Periodic Table of Elements, and at a temperature in the range of 75 to 250 C. to give trans-1,2-bis (aminomethyl)cyclobutane and 3-aza(3.2.0)bicycloheptane.

It has also been discovered, in accordance with the objects of this invention, that the preferred conditions for the preparation of trans-1,2-bis(aminomethyl)cyclobutane in high yield require the use of trans-1,2-dicyanocyclobutane as the starting material with the hydrogenation being carried out at as low a temperature as will give an economic rate of react-ion, usually a temperature in the range of 75 to about 150 C.

As another object of this invention, it has been found that trans-1,2-bis(aminomethyl)cyclobutane can be converted into a series of novel and useful polycarboxylamides by polymerizationwith dicarboxylic acids or their amide-forming derivatives.

The starting material, 1,2-dicyanocyclobutane, can be prepared by a process which involves the themal dimerization of acrylonitrile. This preparation was first described by Coyner and Hillman, J-. Amer. Chem. Soc., 71, p. 324 (1949). However, the conditions of reaction described by Coyner and Hillman resulted in considerable loss to tarry, resinous polymeric byproducts. A much improved process for the dimerization of acrylonitrile to 1,2-dicyanocyclobutane is described in an application, Serial "ice Number 857,557, filed December 7,. 1959, by William L. Lehn and George R. Nacci, and now abandoned.

It is known that these processes for the dimerization of acrylonitrile yield a mixture of the cisand trans-geometric isomers of 1,2-dicyanocyclobutane. These isomers can be separated by fractional distillation into two fractions which, after recrystallization, have boiling points, under 6 mm. pressure, of 123 C. and 165 C., respectively. Both pure isomers are solids; after recrystallization from ether-ethanol, the melting point of the lowerboiling isomer is 37-38 C. and the melting point of the higher boiling isomer is 7273 C. According to the rule of Von AuWers-Skita (see Steric Effects in Organic Chemistry, ed. M. S. Newman, page 20, John Wiley 8: Sons, Inc., New York), the higher boiling and higher melting isomer should have the cis-configuration. This assignment was confirmed by measurement of the dipole moments: the dipole moment of the low-melting isomer (trans-form) is 4.3 Debyes and the dipole moment of the high-melting isomer (cis-form) is 6.0 Debyes.

Since the preferred process for the production of trans- 1,2-bis (aminomethyl)cyclobu-tane requires the use of trans-1,2-dicyanocyclobutane as the starting material an aspect of the present invention is the discovery of a process for converting c-is-l,Z-dicyanocyclobutane to trans-1,2- dicyanocyclobutane. In accord with this aspect of the invention, it has been discovered that nickel or cobalt hydrogenation catalysts will isomerize the cis-isomer to-the trans-isomer at temperatures in the range of about to 350 C. While isomerization does occur in the liquid phase under these conditions, it is preferable for highconversion and recovery, to employ a vapor phaseisomerizas tion step at 250 to 350 C. A mixture consisting of the cisand trans-isomeric LZ-dicyanocyclobutanes, usually with the cis-isomer present in at least 50%, is vaporized and passed, continuously over a bed of a cobaltor nickel hydrogenation catalyst at -a temperature'in the range of 150 to 350 C., preferably in the range of 250 to 350 C. It isessential that no molecular hydrogen be present in thisvapor phase process. The effluent is separated into the cis-.- and trans-isomers by fractional distillation, and the trans-isomer is then hydrogenated in the liquid phase in accordance with the process of this invention. while the cis-isomer is recirculated to the vapor phase isomeriza, tion step.

Hydrogenation catalysts which have been found operable for the conversion of 1,2-dicyanocyclobutane to trans-1,2-bis(aminomethyl)cyclobutane comprise Raney nickel and Raney cobalt, and the reduced oxides of the transition elements of Group VIII of the Periodic Table. Cobalt and nickel are the preferred catalysts since they are particularly effective in isomerizing cis-1,2-dicyanocyclobutanes to the trans-isomers. These catalysts may be supported on silica, alumina, or carbon, or they may be prepared by reduction of the pure metal oxides or salts. Whether supported or unsupported, these Group VII-l reduced metal catalysts are activated by hydrogenation prior to use, Also effective are the molybdites with Group VHI metal cations, particularly cobalt or nickel molybdite.

While, as indicated hereinabove, the preferred process for the production of trans-1,2-bis(aminomethyD'cyclobutane employs the trans-1,2-tlicyanocycl'obutane isomer as starting material, the mixture of isomers as obtained from the dimerization' of acrylonitrile is also suitable. When the mixture is employed, there is obtained as a by-product a novel secondary amine, 3 -azo(3.2.0)bicycloheptane; no evidence is found for the presence of any of the theoretically-possible cis-LZ-(aminomethyl) cyclobutane, so it is believed that this isomer is completely converted to 3-aza(3.2.0)bicycloheptane under the conditions of the reaction.

Therefore, the reactions occurring inv the process of nomethyl)cyclobutane boiled at 50-65 C./l mm. Hg. this invention can be indicated by the following equa- This was refined by atmospheric pressure distillation in tions: a three-foot, platinum, spinning-band column. yielding S t t UHF C-CEN cat. CH2 O HzNHg Hzv H2CH N11 CHOII GEN CH NHg trans-1,2-dicyanotrans-1, 2-bis (aminocyclobutane methyl) cyclobutanc II III /NII" 00.01- l cure-0 Nicat. CHFCF'OZN NH on,-oo1r2Nrn l CHzCOH; H 1? H CI-I3-O-CEN cat. 1

H2 H2 IIZ(ECEN NE;

| H2CCHz OHZCCH2NHZ NH NH; CH; ,CCH NH CH; GHZ H I eis-1,2-dieyano- 3-8-28 (3.2.0) bicyclocyclobutane V heptane It is not certain by which route 3-aza(3.2.0)bicyclohepparts of center cut having a boiling pointof 193-193.5 tane is formed, so alternative routes are indicated in the at} C./atmospheric pressure; 1 =1.4778. This product equatlons was sub ected to elemental analysis and to determination Ithas been found that when the liquid phase hydroof its neutral equivalent with the following results: genation of mixtures of cisand trans-1,2-dicyanobutane is carried out in the presence of cobalt or nickel catalysts, calculated Found the proportion of diamine to bicyclic secondary amine obtained may be greater than Would be Predicted from IPercent C 63.1 631-6336 the proportion of trans-isomer in the starting material, P rcent H 12.29 12.s0;12.55

- I PQIGBMN Therefore, some rsomerization does occur in the liquid Neutral Eq 57 56 phase under these conditions. In view of this, it is sur- Prismg that adiponitl'fle is not a major Product under 40 A re etition of the above experiment in which the Raney these conditions Since? as disclosed in my copmding nickel catalyst was replaced by a Raney cobalt catal st plication, Serial Number 36,702, filed June 17, 1960, and gave Substantially equizalent products y now U.S. Patent No. 3,092,654, similar catalysts convert 1,2-dicyanocyclobutanes exclusively to adiponitrile when EXAMPLE 2 hydrogenation is carried out in the vapor phase; under those conditions, ring scission and hydrogenation of the resulting free radicals occur preferentially to reduction of the nitrile groups.

The following examples are provided to illustrate the invention but it is not intended to limit the invention thereto, since it is obvious that many variations embraced by the above descriptions of the invention are possible and will occur to one skilled in the art of hydrogenation.

In these examples, parts are by weight unless otherwise indicated:

Thirty-five parts of 1,2-dicyanocyclobutane, which distilled at 124.5 to 1 28" 0/9 mm. Hg, 85 parts of anhydrous ammonia, and 5 parts of 5% ruthenium on charcoal catalyst were charged to a steel shaker tube :and processed for one hour at 225 C. under hydrogen at a pressure of 700 atmospheres. The reaction products were separated by distillation, as in Example 1. However, in the instant example, the conversion to diamme was 10.3 parts and the conversion to 3-aza(3.2.0) bicycloheptane was 7.9 parts. The latter product was EXAMPLE 1 r characterized, afterrefractionation; it had a boiling point t of 127-130 C. at atmospheric pressure; 1; =1.4530.

Y P of amlxtilre Conslstmg of cflildfi f y Elemental analysis and determination of the neutral mtnle dimer obtained from thermal drmenzatlon of i l t f thi bicycfi secondary amine c ave h f lacrylonitrile (a mixture or cis-1,2-dicyanocyclobutane lo i lt a and trans-1,2-dicyanocyclobutane containing approxi- 6 mately 40% cis-isomer and trans-isomer), parts anhydrous ammonia, and 5 parts of a Raney nickel catalyst were charged to a high-pressure steel shaker tube Calculated Found and processed for one hour at C. 111K1 1? hyd g n 1: gs

at a pressure of-600 atmospheres. G5 P 14:4 3 9 The shaker tube was cooled, the pressure vented, and 6mm Eq 97 102; 102

the contents discharged, the tube was rinsed with metha- Y n01. Catalyst was removed by filtration. The product EXAMPLE 3 mixture comprised trans 1,2 bis(aminomethyl)cyclo- One hundred and twenty parts of a mixture of cisand butane, and 3-aza(3.2.0)bicycloheptane, together with 7 trans-1,Z-dicyanocyclcbutane isomers, 255 parts anhymethanol wash. The latter was separated .by distillation. drous NH;,, and 44 parts Raney nickel catalyst were The reaction products were separated by crude fractional charged to a stainless steel agitated autoclave and procdistillation at 1 mm. pressure, and 17 parts of the crude essed for one hour at 156 C. under 500 atmospheres diamine was obtained as well as a fraction comprising 3- of hydrogen pressure. The pressure was vented and the aza(32.0.)bicycloheptane. The crude trans-1,2-bis(ami- 75 contents ot'the autoclave rinsed outwith cc. of

methanol and filtered to remove catalyst. The filtrate was charged to a'stillpot and the methanol remove-d by distillation;

The reaction products were then crudely fractionated by distillation to separate a center cut from foreshots'and heel."

The center cut, 91.7 parts, were charged to the stillpot under 'a spinning band c-olumnand fractionated by distillation at atmospheric pressure. The results of this Cut 2 was analyzed as the center cut consisting of pure 3-aza(3.2.0)bicycloheptane and Cut was analyzed as the center cut consisting of pure trans-1,2-bis(aminomethyl)cyclo'butane. v

OUT 2 a-AZA(aamBroYLoonEPTANm Calculated Found Percent 0-..- 74. 3 74. 7; 74. 3 Percent H 11.33 11.9; 11.6 Percent N Y 14. 4 14. 13;.14. 20 Neutral Eq 97 08; 99

The infrared spectrum of Cut 2 showed a band at 305 characteristic of a single N-H bond as required by the assigned structure.

CUT 5 [TBANS-1,2-BIS(AMINOMETHYL)OYCLOBUTANE] Calculated Found Percent G 63.1 6 .7; 62. 7 Percent H 12. 29 12. 3; 12. 6 Percent N- 24. 56 24.10; 24.24 Neutral Eq 57 57 The infrared spectrum of Cut 5 was measured and found to be consistent with the assigned structure: two N-H stretching bands in the 3p. region; a NH deformation band at 6.2 1; and broad diamine absorption'in the 12 region.

EXAMPLE 4 A catalyst was prepared by reducing 50 'cc. of cobalt oxide in a reaction tube by passing hydrogen at 300 Cfo vefit for several hours. The hydrogenwas displaced with'n'itrogen. Then a feed consisting of 72% cisand 28% trans l,Z-dicyanocyclobutane was vaporized and passed through the tube with N gas as carrier at a rate .to give about 5 seconds contact time. Three temperature ranges were tried. The eifluent was condensed'and subsequently analyzed by gas chromatography. Results areshown in Table B.

Table- B ISOMERIZATION OF (118- TO TRANS-1,2-DIOYANOCY- CLOB UTANE Percent Percent Percent Percent Temp, C. CcJNz Rec. Trans- 015- Low Boilers a'reduced nickel oxide catalyst.

6 EXAMPLE 5 A stirred, stainless steel autoclave equipped for continuous addition and removal of liquid was charged with a cobalt catalyst prepared as described in Example 4 and with. trans-1,2-dicyanocyclobutaneprepared as describedinvEx'ample .4. Thelautoclave was pressured to 600 atmospheres with hydrogen and the contents stirred and heated to, and maintained at, to C. Trans 1,2 dicyariocycl-obutane was continuously added and'product stream removed at such a rate as to provide a 30-minute average contact time.

The liquid'efiiuent was separated by fractional distillation' to recover the lower-boiling fraction, and the higherboiling residue, unreacted trans-1,2-dicyanocyclobutane :The lower boiling fracwas recycled to the autoclave. tion "consisted essentially of only trans-1,2-bis(aminomethyDcyclobutan'ewhich was further refined by distillation. i i I I In another experiment, similar results were achieved using a reduced nickel oxide catalyst for the hydrogenation. i

[The novel polyamides with which this invention is concerned'are fiber-forming, synthetic poly-carboxylamides in'w'hich the carboxyl-amide linkages form an integral part ofthe polymer chains and which, upon hydrolysis,

yield trans-11,2-bis(aminomethyl)cyclobutane, and at least one dicarboxylic' acid selected from the group consisting of aromatic dicarboxylic acids and linear aliphatic dicarboxylic'acids having from two to twelve carbon atoms in the'mole'cule'.

.The 'polyamides of this invention can be prepared by polymerization of salts prepared by reaction of equivalent proportions' of diamine and dicarboxylic acid. In a typical procedure, solutions of equivalent amounts of diamine and of dicarboxylic acid in a polar organic solvent for ant, crystalline salt which precipitates is heated, in an autoclave in an inert atmosphere under autogeneous pressure at a temperature'in the range of 220 to 300 C. until polymerization under these conditions is substantially complete (about one to three hon-rs), then, to complete the polymerization, the autoclave is evacuated and the heating continued under reduced pressure with a nitrogen bleed until the evolution of water substantially ceases. Another, alternative procedure which can be employed is to react the diarnine with an amide-forming derivative of the dioarboxylic acid, such as an acid chloride. Where ac d chlorides are employed, it is preferable to add a base to neutralize the evolved I-lCl. A convenient process employing acid chlorides involves interfacial polymerizatron in which the acid chloride, dissolved'in a water-immiscible solvent, is dispersed in an aqueous medium to which the diamine and sodium hydroxide are added in equivalent proportions.

Aromati'ddicarboxylic acids Which can be employed forthe' preparation of'the polyamides of this invention include terephthalic acid, isophthalic acid, 4,4-dicarboxydiphenyl ether, diphenic acid and naphtha'lic acid. Aliphat-ic dicarboxylic' acids which can be employed for the preparation of the polyarnide of this invention include oxalic acid, adipic acid, sebacic acid, undecandioic acid, and dodecandioic acid.

For certain purposes, particularly for the preparation of 'polyamides for melt-spinning, it has been found that the polymerization of trans-1,2-bis(aminomethyl)cyclobutane with a mixture of dicarboxylic acids consisting of anaromatic dicarb'oxylic acid and a linear aliphatic dicarboxylic acid provides particularly valuable polyamides. By varying the proportion of aromatic to aliphatic dicarboxyli'c acid, polyamides having any desired melting point intermediate between the melting points of the polyamides 'obtainedwith' either 'dicarboxylic acid alone, can be obtained.

The polycarboxylamides of this invention are useful for the preparation of textile fibers, both monofilaments and. yarns. They can be employed as molding granules for the fabrication of shaped articles by extrusion and by injection molding. Fibers, tubing, and pipe are examples of useful articles which can be made by extrusion of these polyamides. Gears, housings, containers, door handles and the like can be made firom these polyamides by injection molding. These polyamides are more transparent than many of the nylons previously known to commerce, making them unique in applications where transparency is desired, particularly in films and containers. Because of their optical properties, they can be.

As an example of the preparation of a nylon from trans-1,2-bis(aminornethyl)cyclobutane, a salt was struck, in ethanol, between equivalent amounts of trans-1,2-bis (aminomethyncyclobutane and pure 'adipic acid: A quantitative yield of the crystalline salt was obtained; this salt had a melting point of 197199 C. This salt was sealed in a glass tube under N atmosphere and heated for 2 hours at 245 C. under autogeneous pressure. The prepolymer obtained was colorless; it was further polymerized by heating at 225 C. under a vacuum with N bleed to. .carry oif evolved water. The final polyamide was transparent. It had a softening point of 85 90 C. and had a high molecular weight, as judged from its solu tion viscosity in meta-cresol (1 =1.3). This nylon is a tough plastic for use in low temperature applications and as a nylon for. either solution or dispersion coating of fabric substrates, paper, and the like.

EXAMPLE 7 As another example of the preparation of a nylon polymer from the novel diarnine of this invention, an inter-facial polymerization was carried out. Amixture of 150 ml. H O, 0.5 g. sodium lauryl sulfatetas dispersing agent), 50 ml. toluene, and 10.15 g. isophthaloyl chloride was vigorously stirred to give a dispersion of the organic phase in the aqueous phase. There was then added all at once a mixture of 75 ml. H O, 4.2 g. NaOH, and 5.7 g. trans-1,Z-bisCam-inomethyl)cyclobutane. The temperature rose to about 70 C., and a solid polycarboxylamide was precipitated. This polyamide was col- :lectedby filtration, washed with 10% aqueous NaOH and twice with'water. After drying overnight in a vac-. 'uum oven at 100 C., the yield of polymer was found to be 9.6 g.; M.P.=200220 C.; 7 :0] (meta-cresol). This high-melting nylon is particularly useful in the preparation of yarns and filaments with unique properties including high modulus which makes it a valuable fiber for crease-resistant, wash-and-wear textiles.

EXAMPLE 8 A salt was struck, following procedure of Example 6, between equivalent amounts of trans-1, 2bis(aminomethyl)cyclobutane and pure sebacic acid. The crystalline salt was isolated and heated, under autogenous pressure, in a sealed reactor at 250 C. for two hours. The pressure was released and a N bleed passed through the melt for /2 hour at a temperature of 283 C. The polymerization was completed by heating under vacuum at 283 C. for /2 hour. The resultant polymer, on cooling, was a tough, white solid plastic. Its inherent viscosity, measured at C. in meta-cresol at a concentration of 0.5 g./ 100 ml. solvent, was 0.74. This polymer had a melt temperature of 170 C. and a stick temperature of 143" C. The melt temperature was determined as the lowest temperature at which a small pellet melted when placed on a preheated block; the temperature was raised in increments of 25 C. until the temperature was reached at which a solid pellet rapidly liquified upon contact. The stick temperature was determined by touching a piece of solid polymer to a heated block; the temperature at which the polymer would stick and then could be pulled out to a fine filament was taken as the stick temperature.

EXAMELE 9 A salt was struck, following the procedure of Example 6, between equivalent amounts of trans-1,2- bis(aminornethyl)cyclobutane and pure terephthalic acid. The crystalline salt was isolated and heated, under autogenous pressure, in a sealed reactor at 295 C. for one hour. The pressure was released and a N bleed passed over the prepolymer for one hour at a temperature of 295 C. The polymerization was completed by heating under vacuum at 295 C. for one hour. The resultant polyamide was extremely high melting, having a melt temperature higher than350 C. This polymer was insoluble in meta-cresol but had an inherent viscosity of 0.40 at 25 C. when determined in sulfuric acid at a concentration of 0.5 g./ ml. of solvent.

EXAMPLE 10 A prepolymer was prepared by refluxing a mixture of tran -1,2-bis(aminomethyl)cyclobutane with excess di-n-butyloxylate. A solid prepolymer (low molecular weight polyamide) precipitated and was isolated. This solid prepolymer in the form of a powder was heated in a tubular reactor with N passing through at 283 C. for 2% hours. The resultant polyamide had a melt temperature of 337 C. and an inherent viscosity of 0.35, determined in concentrated sulfuric acid at 25 C. at a concentration of 0.5 g./ 100 ml. solvent. This polyoxamide was insoluble in meta-cresol.

The novel secondary bicyclic amine, 3-aza(3.2.0)bicycloheptane, provided by the process of this invention, is useful as an intermediate in the preparation of several novel and useful compounds. By reaction with CS it is converted into acarbarnate which is effective as a rubber accelerator and it isuscful as an ingredient in herbicides and fungicides. Conversion of the 3-aza- (3.2.0)bicycloheptane to a series of quaternary ammonium compounds by reaction with alkyl halidesprovides a new series of quaternary ammonium compounds useful as surfactants and in pharmaceutical preparation. 3-aza- (3.2.0)bicycloheptane is itself effective as a catalyst for the polymerization of epoxidesand other ionic catalyzed polymerizations.

I claim: 7

l. The compound trans-1,2-bis(aminomethyl)cyclobutane.

2. A process for the preparation of trans-1,2-bis- (aminomethyl)cyclobutane which comprises isomerizing cis-l,2-dicyanocyclobutane to trans-l,2-dicyanocyclobutune by passing a mixture comprising cis-l,2-dicyanocyclobutane in the vapor phase over a hydrogenation catalyst in an inert atmosphere tree of molecular hydrogen at a temperature in the range of 250 to 350 C., said hydrogenation catalyst being selected from the group consisting of cobalt metal and nickel metal, supported cobalt metal and supported nickel metal and cobalt molybdite and nickel molybdite, subjecting the efiluent from the vapor-phase isomerization reaction to fractional distillation to separate the higher-boiling, unchanged cis-l,Z-dicyanocyclobutane from the lower-boiling trans- 1,Z-dicyanocyclobutane, and recycling the cis-l,2-dicyanocyclobutane to the isomerization step,and miX 9 trans-1,2-dicyanocyclobutane with anhydrous ammonia and passing said mixture, in the liquid ph Under a pressure of hydrogen in the range of 400 to 1000 atmospheres, over a hydrogenation catalyst at a temperature in the range of 75 to C., said hydrogenation catalyst 9 being selected from the group consisting of an unsup- 2,534,088 ported transition metal of Group VIII of the Periodic 2,576,959 Table of Elements, a supported transition metal of said 2,586,512 Group VIII, and a molybdite salt of a transition metal 2,634,292 of said Group VIII. 5 2,818,431 2,931,789 References Cited by the Examiner 2,9 3 9,862 2,941,954 UNITED STATES PATENTS 3,012,994 2,163,584 6/39 carothers et a1. 260-78 10 3,018,271 2,244,192 6/41 Flory 2 60-78 2,292,949 8/ 4-2 Lazier et al. 260563 2,295,406 9/42 Jolly 260-464 2,386,737 10/45 Bruson 26 0-464 2,469,830 5/49 Knott 260-313 1 2,497,839 2/50 Ralston et a1. 260-313 10 Webb 2-60-563 May et a1 260-563 Burtner et al 260-563 Hellerbaeh 260-563 Beegle 260-563 Wielicki 260-78 Caldwell 260-47 Wilkes 260-570.9 Bell et a1. 260-563 Anderson 2 60-563 OTH-ER REFERENCES Shuikina, C. A., volume 31, page 5332 (1937).

5 CHARLES B. PARKER, Primary Examiner.

HAROLD N. BURSTEIN, LEON ZITVER, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,192,262 June 29, 1965 Ralph Courtenay Schreyer It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 64, for "themal" read thermal column 2 line 67 for "3-azo" read 3-a2a column 3, lines 4 to 27 for that portion of the equation reading cat read t NH NH Column 5 line 27, for "BICYLCOHEPTANE" read BICYCLOHEPTANE.

Signed and sealed this 22nd day of February 1966.

(SEAL) Attest:

EDWARD J. BRENNER ERNEST W. SWIDER Commissioner of Patents Attesting Officer 

1. THE COMPOUND TRANS-1,2-BIS(AMINOMETHYL)CYCLOBUTANE.
 2. A PROCESS FOR THE PREPARATION OF TANS-1,2-BIS(AMINOMETHYLE)CYCLOBUTANE WHICH COMPRISES ISOMERIXING CIS-1,2-DICYANOCYCLOBUTANE TO TRANS-1,2-DICYANOCYCLOBUTANE BY PASSING A MIXTURE COMPRISING CIS-1,2-DICYANAOCYCLOBUTANE IN THE VAPOR PHASE OVER A HYDROGENATION CATALYST IN AN INERT ATMOSPHERE FREE OF MOLECULAR HYDROGEN AT A TEMPERATURE IN THE RANGE OF 250* TO 350*C., SAID HYDROGENATION CATALYST BEING SELECTED FROM THE GROUP CONSISTING OF COBALT METAL AND NICKEL METAL, SUPPORTED COBALT METAL AND SUPPORTED NICKEL METAL, AND COBALT MOLYBDITE AND NICKEL MOLYBDITE, SUBJECTING THE EFFLUENT FROM THE VAPOR-PHASE ISOMERIZATION REACTON TO FRACTONAL DISTILLATION TO SEPARATE THE HIGHER-BOILING, UNCHANGED CIS-1,2-DICYANOCYCLOBUTANE FROM THE LOWER-BOILING TRANS1,2-DICYANOCYCLOBUTANE, AND RECYCLING THE CIS-1,2-DICYANOCYCLOBUTANE TO THE ISOMERIZATION STEP, AND MIXING SAID TRANS 1,2-DICYANOCYCLOBUTANE WITH ANHYDROUS AMMONIA AND PASSING SAID MIXTURE, IN THE LIQUID PHASE, UNDER A PRESSURE OF HYDROGEN IN THE RANGE OF 400 TO 1000 ATMOSPHERES, OVER A HYDROGENATION CATALYST AT A TEMPERATURE IN THE RANGE OF 75* TO 150*C., SAID HYDROGENATION CATALYST BEING SELECTED FROM THE GROUP CONSISTING OF AN UNSUPPORTED TRANSITION METAL OF GROUP VIII OF THE PERIODIC TABLE OF ELEMENTS, A SUPPORTED TRANSITION METAL OF SAID GROUP VIII, AND AMOLYBDITE SALT OF A TRANSITION METAL OF SAID GROUP VIII. 